Easy way for button top battery

Hello everyone, since buying 21700 button top batteries such as Samsung 40T or 30T or Molicel P42A or Vapcell T42 on the market is increasingly difficult because they are not easy to find, I decided to make them at home using a 21mm MCPCB. that Simon Mao sells in his AliExpress shop at the following link:

I will fix the PCB board on the flat top battery head with a transparent shrink film, taking care to leave the upper part uncovered that will touch the head of the flashlight.

Since I am not a technician I ask all BLF members if my idea could be a good one. Thank you.

It seems a bit not stable.
If it tilts the contact is not best.
Consider fill the gap or solder it in place.

Also make sure it is not too high for your light

Thanks so much for the advice, I'll do as you suggest and fill the void with an insulator ...

If you can Solder —Just Solder Blob the top of the cell —- Works great ( No adapter needed )

I did not want to solder it because maybe one day recover the PCB boards maybe when the battery starts to decay as performance but I will also follow this advice and I will weld some to try.

Thanks 1000.

If you have a hard time making the solder blob big enough — I’ve used a piece of balled up copper wire —just fill it full of solder

Use a magnet.


Magnets work well.

As long as the battery compartment does not apply any sideways action when closing.
For example the Q8 or the SP36

All the Best,